Antigens presently available for immunological studies of coccidioidomycosis are limited to coccidiodin, an autolysate of mycelial-phase cells of Coccidiolides immitis, and spherulin, and autolysate of spherules. Regardless of the source, these antigens are crude, heterogeneous mixtures containing multiple components. Studies in our laboratory have, therefore, been directed towards isolating a specific monomolecular antigen from C. immitis. Towards this goal, we have studied the efficacy of an alkali-soluble, water-soluble cell wall fraction designated C-ASWS from mycelia (C-ASWS-M) and from spherules (C-ASWS-S). This cell wall antigen exhibits biological activity in skin tests, lymphocyte transformation assays, and MIF (migration inhibitory factor) assays. In addition, C-ASWS detects tube precipitin (IgM) antibodies which are produced during the early stages of disease and IgE antibodies which are produced throughout this disease. Other studies have established that mice vaccinated with C-ASWS are protected against challenge with viable C. immitis arthrospores. Chemically, C-ASWS is a polysaccharide-protein complex containing mannose, 3-0-methylmannose, glucose, galactose, and at least 16 amino acids. Column chromatography of C-ASWS on Sephadex G-200 yielded three peaks, two of which were homogeneous by two-dimensional immunoelectrophoresis. The objectives of the proposed studies are as follows. C-ASWS will be fractionated using Sephadex G-200 chromatography. The homogeneity of isolated fractions will be established by two-dimensional immunoelectrophoresis. Heterogeneous fractions will be further purified using conventional techniques (ion-exchange chromatography, immunoadsorption). The biological activity of each purified component will be established in cellular immune assays (skin tests, lymphocyte transformation, and MIF) and humoral immune assays (tube precipitin and IgE antibodies) in infected guinea pigs and in patients with active coccidioidomycosis. Vaccine trials will be performed in mice challenged with viable C. immitis spores after immunization with monomolecular fractions. Biologically active fractions will be characterized chemically.